Die-stock.



H. W. os'rEB..

mn sTooK.. APPLIGATON FILEDAPB.. 9, 1906.'

902,599. Patented N0v.3,149.o8.

2 SHEETS-SHEET 1.

H. W. OSTER.

l DIE STOCK. APPLICATION FILED APB. 9, 1906.

Patented N0v.3, 1908.

2 SHEETS-SHEET z.

UNITED SllirlllS, PATENT. OFFICE.

HERMAN W. OS'IAER, OF CLEVELAND, OHIO, ASSIGNOR TO THE OSTER MAN UFACTURING- COMPANY, OF CLEVELAND, OHIO, A CORPORATION OEOHIO'.

specification of Letters Patent.

Patented Nov. 3, 1908.

Application filed April 9, 1906. Serial 310,611.

To all 'whom it may concern.

Be it lgnown that I, HERMAN W. Os'rFR, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State .of Ohio, have invented a certain new and useful Improvement in Die-Stocks, of which the following is a full, clear, and exact description.

The object of this invention'is to provide mechanism wherewithto cut tapered threads upon pipes, tubing and the like,-and particularly on large sizes thereof,by the application of comparativelylittle power. 'l'fhese results are attained by means of the combination of parts hereinafter described, and shown in the drawings, in which Figure l is a central longitudinal section of a die stock embodying'the invention.` Fig. 2 is a plan view thereof with a portion of the cap plate broken away. Fig. 3 is a perspective view of one of the die cages and Fig. 4 is a side elevation of'av modified form of die. Referring to the arts by letters, A representsv the work-ho ding member or shell, which is of tubular form and is adapted to be secured upon the pipe to be threaded by means of set screws ll, or any other suitable means'. a represents an internally threaded sleeve, which is removably fastened into the upper'end of the niemberA by set screwsK or other suitable means. The screw threaded portion of this sleeve is tapered at the same angle which is required onthe pi e to be threaded. The slceve ct is made in ependently of and secured rigidly to the sleeve A, because otherwise theoparts, in the precise form shown, could not b.4 assembled, and because it is possible to easily substitute another sleeve when the threads become Worn or when it is desired to cut the pipe threads either straight or on a different taper. The

sleeve a may, of course, be madeV integrally' with the memb'er A; and the other parts could be made of such form that they could be assembled as required.

B re resents the die-carrying head,-w'\hicl1 is of tu ular form,.and'is provided with a tubular extension b, which is rotatably fitted into the small bore of the shell, whereby said head is guided. This die-carrying head has, 'within the shell, an external gear b which is in mesh with a long pinion g on a shaft G rotatably mounted in a boss c on one side of the shell A.

head y' and two parallel arms j". 'lhe dies,

are fitted between said arms, and their rear ends abut against the head'. The outer surface of the head is curved, tapered and screw threaded so as to fit the tapered internally threaded part of sleeve a. The use of the cage J is not essential, because the dies themselves might have their rear ends tapered and threaded, and might engage directly with the threaded part of the sleeve a. Such a die is shown in Fig. 4.

In use, the pipe to be threaded is passed through the tubular center o f the shell and head substantially into engagement with the dies, and said pipe is fastened into the described tool by means of the set screws I-I. Then a key or handle (not shown) is applied to the squared projecting end gof the shaft G, by means of which said shaft is turned. This, of course, results in the rotation of the head B relative to the shell A, and this-rotation causes said head to movelongitudinally within saidr shell. This combined rotary and advancing' movement of the head causes the dies to cut a thread upon the pipe correspending"y in pitch with the pitch of the threaded part of the sleeve a. Simultaneously the dies and their cages recede in accordance with the taper of the screw threaded interior of the sleeve a, and thereby the thread cut upon said4 pipe has not only a pitch corresponding with lthe pitch of the screw thread a3 but has also a corresponding ta er.

aving described my invention, I claim:

1. The combination of a work-holding member having a tapered and internally threaded portion, a die-carrying head rotatably mounted in said member and having radial guides for the dies, dies movable in said guides, tapered and threaded surfaces at the rear ends of said dies and movable with them and tted to the. i' ternal threadedvportion of the Work holdingA member, and means for rotating the die-Carrying' head Within the work holding member. Y

2. The combination of a work-holding member having a tapered and internally threaded portion, a die-carrying head rotatably mounted in said member and having radial guides for the dies, cages movable in said guides having tapered threaded outer v10 ends in engagement with the threaded part i ber.

In testimony whereof, I hereunto afi'x my 1.,.3

signature in the presence ot two Witnesses. HERMAN W. OSTER. Witnesses:

E. B. GILCHRIST, ELL. THURsToN. 

